Mechanochemical-assisted extraction of flavonoids from bamboo (Phyllostachys edulis) leaves

An efficient mechanochemical-assisted extraction of flavonoids from bamboo (Phyllostachys edulis) leaves was developed. The highest recovery of flavonoids was achieved by grinding the leaves with Na2CO3 (12 wt.%) and Na2B4O7·10H2O (2 wt.%) for 10 min, extraction with water at 25 °C and liquid/solid ratio of 20 mL/g for 15 min. It was compared with heat reflux extraction and alkali extraction, both of which yielded lower recoveries of total flavonoids and representative flavonoids. Mechanochemical processing resulted in particle size reduction and intimate contact between the milled materials. Diffusion was enhanced and flavonoids were converted to be more hydrophilic at room temperature, which promoted the progression of subsequent extraction. It showed the advantages of efficiency, no organic solvent consumption and much lower extraction temperature.

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► Mechanochemical-assisted extraction achieved high recovery for flavonoids.
► Milling with solid reagents rendered flavonoids more hydrophilic at room temperature.
► Enhancement of diffusion and chemical transformations promoted subsequent extraction.
► Advantages are high efficiency, no organic solvent and room temperature.